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Nearly all the sports practised nowadays are competitive.

現在開展的體育運動幾乎都是競爭性的。

Yet a great many processes depending on such research are sought for with complete secrecy until the stage at which patents can be taken out.

然而，依賴這種研究的很多工藝程序是在完全保密的情況下進行的，直到可以取得專利權的階段為止。

if you think what it must be like to share the deck of a ship with several squadrons of jet aircraft,

因此，如果你能想像出同在一個甲板上是什么滋味兒的話，和幾個中隊的噴氣機。

He mentally visualizes a complex form from all round itself;

他的大腦能從物體周圍的各個角度勾畫出其復雜的形象，

For our purposes, we are concerned only with one kind of cost----

就我們的目的而言，我們只關心一種費用-

only of metal, which wears away by friction.

而是由金屬組成，而金屬可以隨著磨擦而磨損殆盡。